1. Field of the Invention
This invention relates to heat insulation for industrial furnaces and the like, and more particularly to a retainer system for simplifying the retention of refractory fiber modules as an insulating medium.
The use of refractory fiber for insulating purposes in the lining of industrial furnaces has grown very rapidly in the past several years. Formerly, the most common arrangement was to use blanket linings, but these are being replaced by so-called fiber modules of various shapes and constructions. Most of these modules are produced using blanket material cut into strips and formed into modules, most commonly sized at twelve inches by twelve inches and having various thicknesses from two inches to twelve inches.
2. Background Information
In order that the invention may be appreciated in its proper context, reference may be made to the following background material which is in the form of bulletins of various major manufacturers of heat insulating furnace linings:
1. Carborundum Co. bulletin on FIBERWALL.TM. furnace linings PA1 2. Pyroblock.RTM. bulletin PA1 3. Babcock & Wilcox bulletin on KAOWOOL.RTM. blanket lined furnaces
In the first listed bulletin put out by the Carborundum Company, there is described an installation system for a furnace lining involving a ceramic fiber module constituted of layers of mineral wool block and thermal shock resistant ceramic material. A fastening means includes a stud on which the several linings or layers are impaled; a cup-shaped locking means engages the stud.
Another of the aforenoted bulletins describes a so-called "PYROBLOCK".RTM. system, involving a plurality of ceramic fiber strips bonded to an expanded metal substrate and including a special fastener. The installation procedure with this system includes welding of the fastening stud that is used to the furnace shell after the module as defined has been placed in position against the furnace shell.
The bulletin of Babcock and Wilcox describes the installation of blanket linings over a mineral wool base or substrate. A variety of fastening or anchoring devices are described; however, all of these provide that a nut or locking washer bears against the innermost layer; that is, the layer at the hot interior of the furnace or the like.
It will thus be appreciated that problems remain with respect to the mounting or fastening of blankets or modules of conventional construction to the outer shell of heat treating furnaces. Notably, considerable cost is involved in attempting to retain the lightweight fiber blanket materials utilized in forming a layered fiber module so that the module will be adequately supported mechanically.
It should also be noted that many of the conventional retaining methods as practiced require accurate layout of the furnace shell for prewelding of the anchoring or fastening devices; that is to say, the studs or similar devices that are deployed. It is apparent that such methods are relatively time consuming and costly.
Accordingly it is a primary object of the present invention to achieve firmness of support and security in the fastening or anchoring of refractory fiber modules, while significantly lowering the cost involved.
Another object is to simplify the installation procedure for such fiber modules by permitting the welding or otherwise securing of the fastening stud after the fiber module has been placed in position against the furnace shell.
Yet another object is to insure protection of the fastening or anchoring means from corrosion as a result of being exposed to the hot gases of the furnace; at the same time, substantially to prevent heat transfer from the furnace interior by way of the fastening stud to the furnace shell.